A ring-opened polymer derived from a norbornene-type monomer having no polar group, and its hydrogenated product, have good heat resistance, electrical properties and low water absorption, and therefore are widely used for electrical insulation. However, the polymer and hydrogenated product have poor adhesion to metal such as copper and silicon and glass and other materials, and poor compatibility with other compounds such as a curing agent and an epoxy resin.
A ring-opened polymer derived from a norbornene-type monomer having a polar group has also been proposed. More specifically, a polymer having a plurality of polar groups such as a hydroxyl group is disclosed in Japanese Unexamined Patent Publication No. H5-155988, which is obtained by a process wherein a norbornene-type monomer having an ester group or a hydroxyl group such as an acetate of 5,6-dihydroxymethylbicyclo[2.2.1]hept-2-ene is subjected alone to ring-opening polymerization in the presence of a tungsten-containing catalyst, and then, the resulting polymer is hydrogenated. A polymer having hydroxycarbonyl groups is disclosed in Japanese Unexamined Patent Publication No. H11-52574, which is obtained by a process wherein 8-methoxycarbonyltetracyclo[4.4.0.12,5.17,10]dodec-3-ene is subjected alone or together with bicyclo[2.2.1]hept-2-ene to ring-opening polymerization in the presence of a tungsten-containing catalyst, and then, the resulting homopolymer or copolymer is hydrogenated and further hydrolyzed. These polymers exhibit improved adhesion to some extent as compared with a polymer having no polar group, but, having high water absorption, and exhibit a long transmission retardation time for a high frequency signal in a GHz region, and tend to produce a noise. Further, a high-molecular-weight copolymer prepared by copolymerization of the above-mentioned norbornene-type monomer having a polar group with a bicyclio norbornene-type monomer has a low glass transition temperature Tg and poor heat resistance.